Portola Valley dates to 1964, and 3 of its places are on the National Register
More historic than 39% of U.S. towns · #240 of 847 in California. What drives it
Most of Portola Valley was built recently: 9% of its homes predate 1940 and the median home dates from 1966. Its Register listings are the Casa de Tableta, the Portola Valley School and the Our Lady of the Wayside. Below: 3 old photos and papers, maps from 1897 on, and the census since 1970.
Founding year: Wikipedia. First post office: 1894.The full story ↓
History grade
What drives Portola Valley’s History grade
On its age, its old homes and the National Register, Portola Valley is more historic than 39% of U.S. towns, #240 of 847 in California. Its National Register listings hold the grade up; its age pulls it down.
C+
HistoryA character grade: shown, never part of Portola Valley’s overall grade.
Few California towns list much on the Register (a typical California town has 0.0 per 10,000 residents, the U.S. 2.4), so Portola Valley’s 13.9 sits above most of its state (93% of California towns have fewer) while its 6 historic buildings outnumber those of 72% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from D to B+. The pre-1940 share is a Census survey estimate (±4.7 points). Two sources give 1964.
Founding year: Wikipedia (other dates in Quick answers). Homes: Census ACS 2020–24. National Register: National Park Service, May 2026 list; each listing counted once (boundary changes and added documentation belong to their listing), and a historic district counts its contributing buildings. How TownRatings grades history →
What stands out about Portola Valley’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Every edition of the U.S. Geological Survey’s map of Portola Valley. Tap a year, or press play to watch the town change.
1897Palo Alto sheet · 1:62,500
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Portola Valley.
Portola Valley was named for Spanish explorer Gaspar de Portolá, who led the first party of Europeans to explore the San Francisco Peninsula in 1769.
The Native Americans already present were Ohlone and specifically the group (or groups) known as Olpen or Guemelento but these were later moved to Mission Dolores and Mission Santa Clara de Asís which claimed the land and peoples.
The area's written history dates back to 1833, when a square league of land was given to Domingo Peralta and Máximo Martínez by Governor José Figueroa to form the Rancho Cañada del Corte de Madera. In those days it was used for lumbering and cattle grazing.
In 1964, according to Wikipedia’s history of the town. Portola Valley’s post office opened in 1894, and the census of 1970 counted 4,996 people here.
How does Portola Valley rank for history?
Portola Valley is more historic than 39% of U.S. towns, #240 of 847 in California. The History grade combines the town’s founding era, the share of homes built before 1940 and its National Register listings. It’s a character grade, so it isn’t part of the overall grade. How it works.
What is on the National Register in Portola Valley?
Three places: the Casa de Tableta (listed 1973), the Portola Valley School (1974) and the Our Lady of the Wayside (1977).
How old are the homes in Portola Valley?
9% of Portola Valley’s homes were built before 1940 (Census estimate, ±4.7 points), against a typical 3.4% for a California town; the median home was built in 1966.
Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021).
From Wikimedia Commons (6), the Library of Congress (3), Wikidata (2), the National Register of Historic Places (3), Wikipedia, Wikidata and Wikipedia for famous people, U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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